Tri color kinescope aging conveyor carrier



Dec. 15, 1959 NASH ET AL 2,917,357

TRI COLOR KINESCOPE. AGING CONVEYOR CARRIER Filed April 5, 1957 2 Sheets-Sheet 1 Dec. 15, 1959 E NASH Em 2,917,357

'I RI COLOR KINESCOPE AGING CONVEYOR CARRIER Filed April 5, 1957 2 Sheets-Sheet 2 E ass/v. E. HUFFMAN/V United States Patent O TRI COLOR KINESCOPE AGING CONVEYOR CARRIER Thomas E. Nash and Eugene E. Hotfmann, Lancaster,

Pa., assignors to Radio Corporation of America, a corporation of Delaware Application April '5, 1957, Serial No. 650,915 '4 Claims. ((1316-27) This invention is directed to a carrier for an endless conveyor and particularly to a novel conveyor and carrier for cathode ray tubes, which is utilized for processing the tubes during their fabrication.

It has been found advantageous to utilize conveyors for transporting cathode ray tubes from one work position to another, during their fabrication. After the cathode ray tube has been assembled, evacuated and sealed off, it is necessary to apply several difierent tests and processing procedures. it has been found further that, such processing of the tubes can be done simultaneously during its transportation from one processing station to another processing station. This requires a conveyor for the tube, which is not only adapted for transporting the tube from one point to another, but which is designed to introduce activating voltages to the electrodes within the tube envelope for performing the appropriate processing procedures. Such processing requires not only the application of low voltages to the several electrodes, but may require the application of a high voltage in the order of 72,000 volts to a portion of the tube. It is, thus, a requisite that the conveyor system be adapted not only to connect the several tube electrodes to appropriate voltage sources but also that the high voltage conductors be properly insulated from low voltage and grounded por-,

tions of the conveyor to prevent dangerous arcing or short-circuiting.

It is therefore an object of the invention to provide a novel conveyor device for cathode ray tubes.

It is another object of the invention to provide a novel conveyor for cathode ray tubes which is designed for applying activating voltages to the tube parts.

It is a further object of the invention to provide a novel processing conveyor for cathode ray tubes in which several voltages can be applied to the tube parts.

It is also an object of the invention to provide a novel conveyor for cathode ray tubes, which is designed for applying high and low voltages to the tube parts for processing the cathode ray tubes during transportation from one station to another.

The invention is in a conveyor device for transporting cathode ray tubes from one station to another during tube fabrication. The conveyor includes a plurality of tube carriers. Each carrier includes brushes for contacting conductive bus bars arranged parallel to the path of the conveyor. The brushes are for providing appropriate activating and processing voltages to the tube electrodes during the time the tubes are being conveyed from one station to another. Low activating voltages are available at one portion of each carrier, while a high voltage in the order of 72,000 volts is available at another portion of the carrier. The two carrier portions are separated by an effective insulating means to prevent dangerous arcing or short-circuiting. Appropriate means are used for applying both the high and low voltages to the tube elements.

Figure 1 is a partial view of the conveyor device ineluding a single carrier in accordance with the invention.

Patented Dec. 15, 1959 ice Figure 2 is an enlarged view of a portion of the carrier of Figure 1 taken along section lines 2-2.

Figure 3 is an enlarged plan view of a portion of the conveyor of Figure 1; and

Figure 4 is a sectional view of the portion of Figure 1 taken along section line 4-4.

In the fabrication of cathode ray tubes, it has been found necessary after the tubes have been exhausted and sealed off to apply to the tube parts, acitvating and aging voltages for predetermined periods of time. Normally, during these periods of time, each tube is somewhat immobilized, in that the tube has-to be stored in a stationary position, where it occupies a considerable amount of space. Furthermore, when the aging and activation of the tube is performed in stationery racks, it is necessary to load the tube into the racks for the aging time, and then to unload the tubes from the racks again, in order that they may be conveyed to subsequent testing and finishing stations. It has been found advantageous, however, to utilize a conveyor system for conveying the tubes from the exhaust and bake-out ovens to the final finishing and testing stations. If the conveyor system follows a sufiiciently circuitous path, it is possible to provide activating and aging voltages to the tubes for a suflicient length of time during its transportation to the final finishing and testing stations. The conveyor can be passed near the ceiling above the work area, so as to avoid taking up work space on the floor. In this way, valuable space used for stationary aging racks is avoided.

During the transporting of the tube by a conveyor as set forth above, the various aging and activating processes require the application of both high and low voltages to the tube elements. It is thus important that the conveyor be designed to handle a large range of voltages without undue danger from arcing and short-circuiting.

Figure 1 discloses part of an aging and activating conveyor for cathode ray tubes, in accordance with the invention. The conveyor includes a plurality of two wheel trolleys 10, each of which is supported by a pair of wheels 12 from the lower flange 14 of an I-beam 16 forminga track for the trolleys 10. The trolleys are connected together at uniformly spaced positions by a flexible connectingchain 18, and as shown in Figure 1.

Figure 1 shows a portion of the conveyor system consisting of asingle carrier 20 for supporting a cathode ray tube 22 (shown in phantom). In accordance with the invention, the single carrier 20 consists of a pendant 24 pivot-ally hung at 26 from a trolley 10. A suspension insulator 28 is pivotally hung at 30 from the lower end of pendant 24, while a carrying yoke 21 is pivotally hung at 32 from the lower portion of the suspension insulator Insulator 28 is fabricated of highly insulating material such as porcelain and includes a large disk 34 interposed between the pendant 24 and the tube carrying yoke 21.

Yoke 21 consists of apair of arms 36 and 37 formed more clearly in Figure 4. Tube supports 38 and 40 con-' i tact the flaring bulb portion 23 of tube 22 and the'bulb is held by gravity, in the manner shown in Figure l. The spacing apart of support structure 38 and 40 is suflicient for an operator to easily load the carrying yoke 21, by

passing the neck 42 of the tube between the supports 38 and 40 and lowering the tube until the bulb portion 23 is contacted. The bulb is unloaded from the carrier,

in the reverse manner. t

The conveyor is urged along the track 16 by power means such as a commercial electrical motor connected t'o'the chain 18.

During the transportation'of the bulb 22 from a station of loading to another station at which the bulb is finished and tested; means are provided foraging andactivating the tube elements within the bulb. This requires'voltages of different amounts ranging up to 72,000 volts. To supply these voltages to the tube 22,'there are fixed to both sides of the pendant 24 terminal" strips 441 Fixed to each of the terminal 'strips 44" are aplurality of contacts 46, 48, 50, 52, 54, 56 and 58. Each ofthese contacts consist of a relatively heavy coil spring 60 having' one end fixed to one of the terminal blocks 44 and the other end terminating in a round spherical contact'62. Along certain portions of the track 16, brass angle bus bars are mounted parallel to the track and in the path of each one of the mounted terminal ends 62. As shown in Figure 2, the round ends 62 of the contacts 46 through 58, each respectively make contact with a diiferent bus bar numbered, 64, 66, 68, 70, 72, 74 and 78 respectively. As shown in Figure 3, the several contacts 46 through 58 respectively extend rearwardly of the direction of motion of the carrier and at an angle to the respective bus bars. Thus, the several contacts may be dragged into the respective bus bars to make contact therewith. The springs 60 of the contacts are sufficiently flexible so that the bus bars may be positioned close enough to the pendant 24 of each carrier to flex the springs 60 when the contacts ride into their respective bus bars. These springs tension the ball shaped contact ends 62' into the V of the bus bars and makes positive contact therebetween. I

Each terminal strip 44 is of an insulating material, so that the several contacts 46 to 58 are insulated from each other and from the conductive metal pendant 24. Each contact is individually connected by a wire 80 (Figure l) to a different terminal, not shown, in a tube socket 82. Wires 80 are formed into a cable 84 extending between the pendant 24 and tube socket 82. Cable 84 may be suspended from an adjacent trolley by a hook 85 so as to relieve the connections of wires 80 to strips 44 of the weight of the cable. The opposite end of the cable is also supported through an insulator 86 from the support structure 38, as shown in Figure 1. A high voltage contact member 88 (Figures 1", 2 and 3-) is fixed to each yoke 21 below its pivot support 32. Contact 88 also includes a spring member 60' and a round contact terminal 62. (Iontact 88 extends out: wardly from the carrier 20 at a difierent angle from the other spring contacts and is positioned in line with a flat bus bar 90 as shown in Figure 3. High voltage itrthe order of 72,000 volts is brought to the tube 22 through the bus bar 90, which is connected to tube 22 through the spring contact 88, the metal. yoke 21-, the metal supports 38 and 40, and a flexible lead 91 with: a spring clip 93 and conductively fixed to support 40. If the bulb portion 22 of the tube is metal, one side of the: spring clip 93 may clamp onto thetube flange 92, for=exampl'e, or any appropriate metal portion of the" bulb. If, however, the bulb' 22 is of glass, the oppositeend of the spring clip 93 is designed so that it may make contact through aconductive cup terminal (not showny sealed through the glass wall of the bulb 22. a

The voltages applied to contacts 46 through 5"8 -a'r'e of relatively low value comparedto the high voltage applied.

to contact 88. Accordingly then, insulator; portion: 34'- electrodes within the tube to one of the wires- 80 con- The tube socket 82. is applied to the base; 94-. of the tube envelope to individually connect the separate tube envelope.

nected to its appropriate spring contact. The tube electrodes may consist of a plurality of spaced conductive elements forming an electron gun 96 mounted within the tube neck 42 of the tube envelope. These electrodes of the electron gun 96 initiate an electron discharge from a thermionic cathode of the gun. This electron discharge is formed by the electrode of gun 96 into an electron beam-,.whicht is accelerated along the axis of the After the carrier is loaded by the operator, it passes along the track 14 into a region inwhich the several spring. contacts, described above, ride into their respective bus bars so as to apply appropriate voltages to the electrodes of the electron gun 96.

A processing operation applied to the cathode ray tube, after it hasbeen evacuated and sealed off, is that of spot-knocking, in which the gun electrodes of the tube are grounded and a conductive coating on the inner surface of thebulb portion 23 of the tube is connected through spring contacts 93' and 88 to the high voltage source in the order of 72,000 volts. The high difference of potential between the grounded gun electrodes and the wall coating, at high voltage, establishes a corona or are discharge within the tube between the gun elements and the coating. This discharge is continued for a period of two minutes and has the function of burning off loose particles which may extend between electrodes within the tube. For this processing step, the bus bars 64 through 78 are grounded, so as to maintain the corresponding gun electrodes at ground potential, While bus bar is connected to the high voltage source. These bus'bars'64 through 78 and 90 extend continuously along.

the-path of the corresponding spring contacts 46 through 58' and 88" for the distance required'for the spot knocking process;

A second processing procedure applied to the cathode ray during its travel is a so-called hot-shot procedure, in which the cathode is activated by putting higher than normal current through the heater filament of the cathode. For example, the heater in the electron gun 96 of the tube is connected to' the two spring contacts 46 and 52. The bus bar 64, to which spring contact 46 makes contact, is connected to a source of low voltage in the order of 14 volts, while the bus bar 70, to which spring contact- 52 makes contact, is connected to ground. In this portionof the conveyor system bus bars 66, 63, 72,74, 78 and- 90' are omitted, and the respective spring contacts 48, 50, 54, 56, 58' and 88' are leftfloating, since the rest of 'the tube electrodes have no potential applied to them during the hot shot step; This procedure is continued for a period of time in the order of two minutes. Heating the cathode above normal temperature appears to activate the 'cath'ode so that its electron emission rises to an optimum value.

In another portion of the conveyor system the cathode ray tube is submitted to an aging schedule for a period of time in. the order of 60 minutes. In this region of 'the conveyor system, voltages are applied. to all of the gun electrodes through the use of the bus bars 64 through 74. For example, bus bar 66 is maintained at a positive 5 volts so as to apply this voltage to the control grid electrode of the gun. Bus bar 64 is maintained at substantially 8 volts while busbar 70 is grounded so as to establish the appropriate current fi'ow through the cathode filamentof the tube. Several hundred volts are applied to the bus bars 68, 72 and 74 respectively so as to apply this voltage totheindividuali accelerating electrodes of. theelectrongun system within the tube neck; The bus bar 78 is-left floating as no potential is required for the focussing, electrode of the gun. Bus bar 90 is omitted in this portion of the conveyor path, and thus no voltage is placed on the conductive coating in the bulb 22 of the tube. The applying of these voltages to the respective gun electrodes of the tube submits the tube to an aging procedure, in; which. the cathode is further activated by an electron; emission front the cathode.

The above described procedures, applied to the tube, during its travel along the conveyor track 14, are only illustrative and in no way are limiting. It is obvious that any desired processing of the bulb, which utilizes the application of electric potentials to the tube elements may be applied during the travel of the tube from one position of the conveyor to another position. By allowing the tube to be processed on a continuously moving conveyor, valuable storage space is eliminated, which would be required if stationary processing equipment were utilized.

The conveyor and carrier structure described above is that in which a large range of voltages may be applied to the tube for any desired period of time. This construction provides a substantial insulating between the low voltage portion of the carrier and the high voltage portion and prevents the danger of arc-over and shorting. The carrier described is of a simple design without the use of complex parts and equipment.

The novel carrier 20 may be utilized in any desired manner, with either a continuous or discontinuous conveyor system. Also, the use of the bus bar arrangement described above is not limiting. As pointed out above, the bus bars at certain portions of the carriers path are discontinuous or may be omitted entirely. A desirable feature which may be incorporated in the bus bar system is one in which, in those regions of the carriers path where the bus bars are continuous, the bus bar may be divided into three-foot sections to electrically isolate one section from another. Power is supplied to each section through series limiting resistors from main power distribution lines. This arrangement is an advantage, for, if a short circuit develops in one of the cathode ray tubes on the conveyor, it will not result in a loading down of the main power distribution lines to a point where all tubes on the line lose power. Such systems are designed so that about percent of the tubes could have shorts without causing loss of applied power to the remaining tubes on the conveyor.

We claim:

1. A processing carrier for a discharge device, said carrier comprising a trolley adapted for movement along a path, a disk-like insulator structure, means pivotally attached centrally to one side of said insulator structure suspending said insulator structure from said trolley, a tube supporting yoke member, means pivotally suspending said yoke-member centrally from an opposite side of said insulator structure, a plurality of low voltage terminal elements fixed to said insulator structure suspending means on said one side of said insulator structure, and a high voltage terminal element fixed to said yoke member on said opposite side of said insulator structure, a plurality of flexible contact members, a different one of said flexible contact members fixed to each one of said low voltage terminal elements, each one of said flexible contact members including a spring having one end fixed to said suspending means and a rounded contact element fixed to the other end of said spring.

2. A tube processing carrier for a conveyor system, said carrier comprising a trolley adapted for movement along a path, a disk-like insulator structure, means pivotally attached centrally to one side of said insulator structure suspending said insulator structure from said trolley, a tube supporting yoke member, means pivotally suspending said yoke member centrally from an opposite side of said insulator structure, a plurality of low voltage terminal elements fixed to said insulator structure suspending means on said one side of said insulator structure, a high voltage terminal clement fixed to said yoke member on said opposite side of said insulator structure, a tube socket carried by said yoke member, and conductive leads joining said low voltage terminal elements to said tube socket, said yoke including a pair of arms joined together at one end and the other ends of said arms being spaced apart and comprising means for supporting a tube therebetween.

3. A tube processing carrier for a conveyor system,

said carrier comprising a trolley adapted for movement along a path, a disk-like insulator, means pivotally attached centrally to one side of said insulator suspending said insulator from said trolley, a tube supporting yoke member, means pivotally suspending said yoke member from said yoke member centrally from an opposite side of said insulator, a plurality of low voltage terminal elements fixed to said insulator suspending means on said one side of said insulator, and a high voltage terminal element fixed to said yoke member on said opposite side of said insulator, a tube socket carried by said yoke member, and conductive leads joining said low voltage terminal elements to said tube socket, said yoke including a pair of arms joined together at one end, the other ends of said arms being spaced apart and comprising means for supporting a tube therebetween, said tube supporting means including a different O-shaped support member fixed to each one of said other ends of said yoke arms. 4. A tube processing carrier for a conveyor system, said carrier comprising a trolley adapted for movement along a path, a flat disk-like insulator, means pivotally attached centrally to one side of said insulator suspending said insulator in a substantially horizontal position from said trolley, a tube supporting yoke member, means suspending said yoke member centrally from a side of said insulator opposite said one side, a low voltage terminal element fixed to said insulator suspending means on said one side of said insulator, and a high voltage terminal element fixed tosaid yoke member on said opposite side of said insulator, said insulator extending in a plane positioned intermediate said high voltage and said low voltage elements.

References Cited in the file of this patent UNITED STATES PATENTS 

